The Emergence of Community-Acquired MRSA

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of hospital-acquired infections worldwide. These strains of Staph. aureus have acquired resistance to many of the antibiotics previously used for treatment of this common infection. In fact, the rate of methicillin resistance in Staph. aureus isolates in critical care units now exceeds 50 percent in US hospitals.

Community-acquired MRSA typically causes skin and soft tissue infections (e.g., boils), but can also present as pneumonia, bloodstream infections or abscesses. Some cases of MRSA have also been reported to cause necrotizing fasciitis, more commonly known as flesh-eating bacterial disease. These infections are frequently noted to cause what looks like an insect or spider bite. The organism is generally faster growing than hospital-acquired strains, however, and infection can spread rapidly, requiring aggressive therapy and, sometimes, surgical intervention.

Infection with MRSA should be suspected in outbreaks of skin boils that are unresponsive to standard antibiotic therapy, especially among participants of contact sports and their close contacts. In general, community-acquired MRSA is more susceptible to antibiotics than hospital strains. However, delaying the start of appropriate antimicrobial therapy may be life threatening.

Traditionally, MRSA infections have been acquired almost exclusively in hospitals, long-term care facilities, or similar institutional settings. Risk factors for acquiring MRSA infection or colonization (presence of MRSA on the body without causing illness) include prior exposure to antibiotics, admission to a critical care unit, surgery and invasive procedures, and exposure to an MRSA-colonized individual.

However, recent reports of virulent and highly transmissible new strains of MRSA have been showing up in places where it had never been seen before. For example, there have been reports of MRSA infections in high school wrestlers and football players, military recruits, and NFL players. The organism is transmitted by skin-to-skin contact with a colonized carrier and can spread in locker rooms through dirty towels and sweat-drenched workout equipment. Turf burns, cosmetic body shaving, and sharing inadequately disinfected whirlpools were implicated in an MRSA outbreak in a Connecticut college football team. Clusters of skin infections caused by MRSA have also been described among injecting drug users, the homeless and incarcerated persons.

The importance of good hygiene in preventing the spread of MRSA in the community cannot be overemphasized. Transmission of MRSA can be prevented by:

Practicing hand hygiene-washing with soap and water or an alcohol-based product